The present invention relates to additive manufacturing, and in particular, to heat treatment of powders used in additive manufacturing.
In the preparation of metal powders for additive manufacturing, the surface of the powder can oxidize very quickly. When the oxidized surface of the powder is exposed to the environment, water can adsorb into the surface and adsorbs on the oxide. Once the powder is used during the additive manufacturing process, the water adsorbed into the powder can cause voids in the formed end-material. Methods of removing water from the additively manufactured materials can cause the formation of hydrogen in the end-material which can make the end-material more brittle.
Previous methods of removing adsorbed water from the metal powder during additive manufacturing include various methods of degassing. Traditional methods of degassing involve the use of very low pressure vacuums and high temperatures. Complications can occur maintaining a very low pressure vacuum during the degassing. Additionally, traditional methods of high temperature heat treatment can cause unwanted sintering of the metallic powder.